/*
 * Copyright 2016 ikidou
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package ikidou.reflect.typeimpl;

import java.lang.reflect.Type;
import java.lang.reflect.WildcardType;
import java.util.Arrays;

public class WildcardTypeImpl implements WildcardType {
	private final Class[] upper;
	private final Class[] lower;

	public WildcardTypeImpl(Class[] lower, Class[] upper) {
		this.lower = lower != null ? lower : new Class[0];
		this.upper = upper != null ? upper : new Class[0];

		checkArgs();
	}

	private void checkArgs() {
		if (lower.length == 0 && upper.length == 0) {
			throw new IllegalArgumentException("lower or upper can't be null");
		}

		checkArgs(lower);
		checkArgs(upper);
	}

	private void checkArgs(Class[] args) {
		for (int i = 1; i < args.length; i++) {
			Class clazz = args[i];
			if (!clazz.isInterface()) {
				throw new IllegalArgumentException(clazz.getName() + " not a interface!");
			}
		}
	}

	@Override
	public Type[] getUpperBounds() {
		return upper;
	}

	@Override
	public Type[] getLowerBounds() {
		return lower;
	}

	@Override
	public String toString() {
		if (upper.length > 0) {
			if (upper[0] == Object.class) {
				return "?";
			}
			return getTypeString("? extends ", upper);
		} else {
			return getTypeString("? super ", lower);
		}
	}

	private String getTypeString(String prefix, Class[] type) {
		StringBuilder sb = new StringBuilder();
		sb.append(prefix);

		for (int i = 0; i < type.length; i++) {
			if (i != 0) {
				sb.append(" & ");
			}
			sb.append(type[i].getName());
		}

		return sb.toString();

	}

	@Override
	public boolean equals(Object o) {
		if (this == o) return true;
		if (o == null || getClass() != o.getClass()) return false;

		WildcardTypeImpl that = (WildcardTypeImpl) o;

		return Arrays.equals(upper, that.upper) && Arrays.equals(lower, that.lower);

	}

	@Override
	public int hashCode() {
		int result = Arrays.hashCode(upper);
		result = 31 * result + Arrays.hashCode(lower);
		return result;
	}
}
